Protective covers

ABSTRACT

A protective cover which is generally in the form of a flexible bellows construction secured at each end by collars in order to define an interior space includes vent means. Thus, when the cover is deformed, the volume within the interior is altered by aspiration or evacuation through the vent means. The vent means includes a vent element in order to allow air or fluid transfer into and out of the interior but prevent ingress of contaminants such as grit and water to the interior.

BACKGROUND TO THE INVENTION

[0001] The invention relates to protective covers and more particularlybut not exclusively to protective covers for protecting moving parts ina mechanism of motor vehicles.

SUMMARY OF THE INVENTION

[0002] According to the invention, there is provided a protective coverfor a motor vehicle joint, the cover having a deformable structuredefining an interior space closed at both ends and including vent meanscoupled to the interior space, the vent means including a vent elementadapted to allow fluid flow thereacross whilst stopping contaminant and/or water entering into the interior space whereby excess fluid pressurewithin the interior can be reduced by fluid evacuation and aspirationthrough the vent means.

[0003] Typically, the fluid will be air.

[0004] Protective covers embodying the invention will now be described,by way of example with reference to the accompanying diagrammaticdrawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

[0005]FIG. 1 is a schematic front elevation of a steering arrangementwith protective covers;

[0006]FIG. 2 is a schematic front elevation of the steering arrangementdepicted in FIG. 1 turned to the right;

[0007]FIG. 3 is a schematic front elevation of the steering arrangementdepicted in FIGS. 1 and 2 turned to the right and subject to suspensionarticulation;

[0008]FIG. 4 is a schematic front elevation of a transmissionarrangement with protective covers;

[0009]FIG. 5 is a cross-section through one of the protective coversembodying the invention;

[0010]FIG. 6 is an enlarged view of the portion of FIG. 5 shown at II;and,

[0011]FIG. 7 is an end view of part of a connector shown in FIG. 6,looking in the direction of the arrow III;

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The protective cover arrangement 10 shown in FIGS. 5 and 6comprises a small diameter sealing collar 12 at one end and a largerdiameter sealing collar 14 at the opposite end, with a plurality ofbellows turns 16 integrally extending between the two ends. In use, thetwo sealing collars are attached to two relatively movable parts of amechanism (not shown) which is to be protected in a motor vehicle. Thecover 10 protects the mechanism from ingress of water, dirt and othercontamination.

[0013] In one particular application of the protective cover shown inFIGS. 1 to 3, two of them are respectively mounted to protect the endsof a steering rack of a steering arrangement 100 in a vehicle. Thus, thesteering arrangement 100 may comprise a steering box 104 operateddirectly by the driver's steering wheel 105 or through the intermediaryof a power steering arrangement. A steering rack extends outwardly inopposite directions from each side of the steering box 104 and is movedaxially in one or the other direction by the steering box in response tosteering action by the driver. The opposite ends of the rack areconnected to turn the steerable wheels 103 of the vehicle. In use, acover 110 extends from one side of the steering box 104, with its largerdiameter fixing collar 114 being secured to the steering box 104 wherethe steering rack extends outwardly therefrom. The smaller diametercollar 112 of the cover 110 is secured to the distal end of the rack.

[0014] At the opposite side of the steering box 104, from which thesecond end of the rack protrudes, a second cover 110 is secured, withits smaller diameter collar 112 fixed to that distal end of the steeringrack.

[0015] The two protective covers 110 thus protect the two end portionsof the rack and the bellows flexibly accommodate axial movement.

[0016] As the steering rack moves to and fro, in order to carry outdesired steering action, the two protective covers 110 will bealternately compressed and expanded as will now be explained in moredetail.

[0017] It will be noted from FIG. 1 that the steering arrangementdepicted has wheels 103 in a straight-ahead configuration. Thus, thesteering box 104 is not displacing the steering rack either to the rightor the left. In such circumstances, the protective covers 110 are notgenerally deformed (that is, not compressed or stretched), and so theinterior volumes of these covers 110 will be substantially at theirdesigned pressure, normally atmospheric. Thus, these covers 110 shouldnot rupture, create noise problems or alter the function of theunderlying steering mechanism.

[0018] In FIG. 2, the steering arrangement of FIG. 1 has been turned tothe right. Thus, cover 110 a is compressed whilst cover 110 b isexpanded. The covers 110 are sealed by collars 112, 114 at each end.Therefore, the compressed cover 110 a would normally be at an elevatedpressure whilst the expanded cover 110 b would be at a reduced pressure.

[0019] Similarly, in FIG. 3, the covers 110 are respectively furtherexpanded (110 b) and compressed (110 a) by suspension 111 movement toaccommodate bumps as the vehicle including the steering arrangementmoves.

[0020]FIG. 4 shows how a similar problem can arise with a drive shaft ortransmission arrangement. A drive shaft 201 extends between an outboardjoint 230 and an inboard joint 231. The outboard joint 230 is supportedby a suspension 233 and the wheel 234. In such circumstances, theprotective covers 232 can be angled and the protective cover 236 can becompressed or expanded. The pressure variation appears only in theinboard joint 231.

[0021] It is necessary to accommodate the resultant changes in pressurein the protective covers. If this is not done, excessive pressure mayrupture the protective covers. One known way of dealing with thisproblem, is to interconnect the interiors of the two covers used atrespective ends of a steering rack. In this way, when one cover iscontracted by movement of the steering rack, the increased pressurewithin the now deformed cover is transmitted to the interior of theother cover which will at the same time be expanded.

[0022] In accordance with a feature of the covers being described, thisinterconnection between the two bellows at opposite ends of the steeringrack is removed in order to allow easier assembly and to reduce costs.

[0023] Referring to FIG. 5, the bellows 10 there shown has a ventarrangement 20 at one end. The vent 20 is L-shaped in form, comprising arelatively long hollow tubular part 22 and a relatively short hollowtubular part 24. Each part 22,24 has an open end 22A,24A. As shown inFIGS. 5 and 6, the vent 20 is secured in position on the cover 10 sothat the end 24A is attached to the wall of the bellows adjacent thelarger diameter collar 14 and with the hollow interior of the part 24thus open to the interior 25 of the cover 10. The part 24 of the vent 20thus extends radially of the major axis of the cover 10 and the part 22of the connector extends in an axial direction.

[0024] Such a bellows 10 can therefore be mounted at one end of asteering rack (for example, as shown in FIGS. 1 to 3) or at one end of adrive shaft (for example, as shown in FIG. 4). A similar bellows wouldthen be mounted at the other end of the steering rack or drive shaft.

[0025] The vent 20 of the bellows 10 at the other end of the rack ordrive shaft would be mounted on the bellows in the same way.

[0026] Each vent 20 is very firmly secured to the bellows 10. A weldingoperation can be used to form a very strong welded bond between thematerial of the vent 20 and the material of the bellows 10. In addition,a mechanical bond is formed between the vent 20 and the material of thebellows 10 where it enters the end 24A of the vent 20. However, the vent20 could be mounted on the bellows 10 by a glueing operation.

[0027] It will be appreciated that the vent 20 can be situated at anydesired position on the external wall of the bellows.

[0028] At the open end of 22 a of each vent 20, a vent element 21 islocated. The purpose of this element 21 is to allow air to pass into andout of the bellows 10 whilst preventing ingress of contaminants andwater to the interior volume 25.

[0029] In effect, the vent 20 and the vent element 21 adjust the volumeof air within the interior so that it is consistent with air pressure.In such circumstances, the vent element 21 acts as a filter to preventtransfer of contaminants, such as grit, grease, etc. and water, into theinterior, allowing relatively free movement of air to adjust the volumeof the interior 25 as the cover 10 is deformed in extension orcompression. In such circumstances, the vent 20 prevents excessive fluid(air) pressure build-up in the interior 25 and will normally maintainthat interior at about atmospheric pressure. Furthermore, with alubricant inside the protective cover 10 it will be understood thislubricant is prevented from escaping and so facilitating continuedlubrication of a protected mechanism.

[0030] The vent element 21 can be formed of a Teflon (Trade Mark)material of calibrated porosity to allow air movement but to preventcontaminants or water entering the interior 25. Clearly, the specificmaterial used is dependent upon the installation requirements; suitableother materials may be used.

[0031] The vent 20 and vent element 21 remove the necessity of aconnecting tube between the pair of protective covers 10. Thus,installation and maintenance of the cover 10 is made less difficult andcostly.

[0032] In order to extend the operational life of vent element 21, itwill be understood that at least a proportion of any contaminants and/orwater will be removed from the element 21 as air or fluids flow out ofthe interior 25.

[0033] This vent works also to avoid any variation of pressure due toexternal temperature or atmospheric pressure variation.

I claim:
 1. A protective cover for a motor vehicle articulating joint,the cover having a deformable structure defining an interior spaceclosed at both ends and including vent means coupled to the interiorspace, the vent means including a vent element adapted to allow fluidflow thereacross whilst stopping contaminants and/ or water enteringinto the interior space whereby excess fluid pressure within theinterior can be reduced by fluid evacuation and aspiration through thevent means.
 2. A cover as claimed in claim 1, wherein the fluid is air.3. A cover as claimed in claim 1, wherein the deformable structure is aflexible bellows.
 4. A cover as claimed in claim 1, wherein thedeformable structure is secured at each end with a respective collarelement.
 5. A cover as claimed in claim 1, wherein the fluid pressurewithin the interior is maintained at a desired fluid pressure.
 6. Acover as claimed in claim 4, wherein the desired fluid pressure is thatof the ambient atmospheric air pressure adjacent the protective cover.7. A protective cover as claimed in claim 1, wherein the vent means islocated at one end of the deformable structure.
 8. A cover as claimed inclaim 1, wherein the vent element comprises a porosity-calibratedmaterial structure.
 9. A cover as claimed in claim 8, wherein thematerial structure is a Teflon.
 10. A cover as claimed in claim 1,wherein the vent element is replaceable in the vent means.
 11. A coveras claimed in claim 1, wherein the vent element is adapted to expel atleast some of any contaminates and/or water associated with it uponoutward fluid movements through the vent element as the deformablestructure and therefore the interior space is deformed.
 12. A cover asclaimed in claim 1, wherein the vent means is configured as a spoutcomprising a first portion outwardly perpendicular to the major axis ofthe cover and a second portion parallel to that major axis of the coverwhereby the vent means has a substantially “L” shaped configuration. 13.A cover as claimed in claim 1, made from an elastomeric material.
 14. Acover as claimed in claim 1, wherein the vent means is arranged to allowfluid air flow thereacross.
 15. A cover as claimed in claim 1, whereinthe vent means is adapted to prevent lubricant escaping from theinterior space.
 16. A cover as claimed in claim 1, wherein the ventmeans is formed separately from the cover and is subsequently connectedto the cover.
 17. A cover according to claim 16 wherein the material ofthe cover enters the vent means to connect the vent means to the cover.18. A cover according to claim 16 wherein the vent means are connectedto the cover by a mechanical bond.
 19. A protective cover arrangement,comprising protective covers as claimed in claim 1 respectively securedabout the ends of a steering arrangement within a motor vehicle in orderto protect that steering arrangement.
 20. A protective cover arrangementcomprising protective covers as claimed in claim 1, secured about amotor vehicle transmission joint to protect that transmission joint.